code: plan9front

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smtp, smtpd: fix use of enc64(), fix memory leaks in doauth()

the approximation of n*2 to calculate the number of output bytes
for enc64() fails for inputs of size < 3. this is fixed by using
encodefmt() which gets the calculation right and also simplifies
the code avoiding the allocation and freeing of intermediate string
buffers.

--- a/sys/src/cmd/upas/smtp/smtp.c

+++ b/sys/src/cmd/upas/smtp/smtp.c

@@ -114,6 +114,7 @@

 	alarmscale = 60*1000;	/* minutes */

 	quotefmtinstall();

+	fmtinstall('[', encodefmt);

 	errs = malloc(argc*sizeof(char*));

 	reply = s_new();

 	host = 0;

@@ -398,10 +399,10 @@

 static char *

 doauth(char *methods)

 {

-	char *buf, *base64;

+	char *buf, *err;

+	UserPasswd *p;

 	int n;

 	DS ds;

-	UserPasswd *p;

 	dial_string_parse(ddomain, &ds);

@@ -414,51 +415,44 @@

 	if (p == nil)

 		return Giveup;

+	err = Retry;

 	if (strstr(methods, "LOGIN")){

 		dBprint("AUTH LOGIN\r\n");

 		if (getreply() != 3)

-			return Retry;

+			goto out;

-		n = strlen(p->user);

-		base64 = malloc(2*n);

-		if (base64 == nil)

-			return Retry;	/* Out of memory */

-		enc64(base64, 2*n, (uchar *)p->user, n);

-		dBprint("%s\r\n", base64);

+		dBprint("%.*[\r\n", strlen(p->user), p->user);

 		if (getreply() != 3)

-			return Retry;

+			goto out;

-		n = strlen(p->passwd);

-		base64 = malloc(2*n);

-		if (base64 == nil)

-			return Retry;	/* Out of memory */

-		enc64(base64, 2*n, (uchar *)p->passwd, n);

-		dBprint("%s\r\n", base64);

+		dBprint("%.*[\r\n", strlen(p->passwd), p->passwd);

 		if (getreply() != 2)

-			return Retry;

+			goto out;

-		free(base64);

+		err = nil;

 	}

 	else

 	if (strstr(methods, "PLAIN")){

-		n = strlen(p->user) + strlen(p->passwd) + 3;

-		buf = malloc(n);

-		base64 = malloc(2 * n);

-		if (buf == nil || base64 == nil) {

+		n = strlen(p->user) + strlen(p->passwd) + 2;

+		buf = malloc(n+1);

+		if (buf == nil) {

 			free(buf);

-			return Retry;	/* Out of memory */

+			goto out;	/* Out of memory */

 		}

 		snprint(buf, n, "%c%s%c%s", 0, p->user, 0, p->passwd);

-		enc64(base64, 2 * n, (uchar *)buf, n - 1);

+		dBprint("AUTH PLAIN %.*[\r\n", n, buf);

+		memset(buf, 0, n);

 		free(buf);

-		dBprint("AUTH PLAIN %s\r\n", base64);

-		free(base64);

 		if (getreply() != 2)

-			return Retry;

-	}

-	else

-		return "No supported AUTH method";

-	return(0);

+			goto out;

+		err = nil;

+	} else

+		err = "No supported AUTH method";

+out:

+	memset(p->user, 0, strlen(p->user));

+	memset(p->passwd, 0, strlen(p->passwd));

+	free(p);

+	return err;

 }

 char *

--- a/sys/src/cmd/upas/smtp/smtpd.c

+++ b/sys/src/cmd/upas/smtp/smtpd.c

@@ -120,6 +120,7 @@

 	netdir = nil;

 	quotefmtinstall();

 	fmtinstall('I', eipfmt);

+	fmtinstall('[', encodefmt);

 	starttime = time(0);

 	ARGBEGIN{

 	case 'a':

@@ -1587,7 +1588,7 @@

 void

 auth(String *mech, String *resp)

 {

-	char *user, *pass, *scratch = nil;

+	char *user, *pass;

 	AuthInfo *ai = nil;

 	Chalstate *chs = nil;

 	String *s_resp1_64 = nil, *s_resp2_64 = nil, *s_resp1 = nil;

@@ -1674,7 +1675,6 @@

 		goto bomb_out;

 	}

 	else if (cistrcmp(s_to_c(mech), "cram-md5") == 0) {

-		int chal64n;

 		char *resp, *t;

 		chs = auth_challenge("proto=cram role=server");

@@ -1683,11 +1683,7 @@

 			reply("501 5.7.5 Couldn't get CRAM-MD5 challenge\r\n");

 			goto bomb_out;

 		}

-		scratch = malloc(chs->nchal * 2 + 1);

-		chal64n = enc64(scratch, chs->nchal * 2, (uchar *)chs->chal,

-			chs->nchal);

-		scratch[chal64n] = 0;

-		reply("334 %s\r\n", scratch);

+		reply("334 %.*[\r\n", chs->nchal, chs->chal);

 		s_resp1_64 = s_new();

 		if (getcrnl(s_resp1_64, &bin) <= 0)

 			goto bad_sequence;

@@ -1720,8 +1716,6 @@

 		auth_freeAI(ai);

 	if (chs)

 		auth_freechal(chs);

-	if (scratch)

-		free(scratch);

 	if (s_resp1)

 		s_free(s_resp1);

 	if (s_resp2)